/*
 * p3649.cpp
 *
 *  Created on: 2013-7-20
 *      Author: zy
 */
#include<cstdio>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<algorithm>
using namespace std;
const int INF = 0x3f3f3f3f;
const int maxn = 1010;
struct node
{
	int x, v;
} a[maxn];
int n, x, v;
int dp[maxn][maxn][2], s[maxn];
int cmp(node a, node b)
{
	return a.x < b.x;
}
int main()
{
	while (scanf("%d%d%d", &n, &v, &x) != EOF)
	{
		for (int i = 1; i <= n; i++)
			scanf("%d%d", &a[i].x, &a[i].v);
		a[++n].x = x;
		a[n].v = 0;
		sort(a + 1, a + n + 1, cmp);
		s[0] = 0;
		for (int i = 1; i <= n; i++)
			s[i] = s[i - 1] + a[i].v;
		int res = 0;
		for (int i = 1; i <= n; i++)
			if (a[i].x == x)
			{
				res = i;
				break;
			}
		for (int i = 1; i <= n; i++)
			for (int j = 1; j <= n; j++)
				dp[i][j][0] = dp[i][j][1] = INF;
		dp[res][res][0] = dp[res][res][1] = 0;
		for (int i = res; i >= 1; i--)
			for (int j = res; j <= n; j++)
			{
				if (i == j)
					continue;
				dp[i][j][0] = min(dp[i][j][0], dp[i + 1][j][0]+(a[i+1].x-a[i].x)*(s[i]+s[n]-s[j]));
				dp[i][j][0] = min(dp[i][j][0], dp[i + 1][j][1]+(a[j].x-a[i].x)*(s[i]+s[n]-s[j]));

				dp[i][j][1] = min(dp[i][j][1], dp[i][j - 1][0]+(a[j].x-a[i].x)*(s[i-1]+s[n]-s[j-1]));
				dp[i][j][1] = min(dp[i][j][1], dp[i][j - 1][1]+(a[j].x-a[j-1].x)*(s[i-1]+s[n]-s[j-1]));
			}
		printf("%d\n",v*min(dp[1][n][0],dp[1][n][1]));

	}
	return 0;
}
